The Post has uncovered an evil, stealthy assault on Christmas and it's coming from a place you'd least expect it — the YMCA! Yes, Manhattan's McBurney Y is snubbing Santa Claus for Frosty the Snowman at this year's kids luncheon.

Today in an "EXCLUSIVE," New York's favorite litter box liner attacks the "politically correct West Village YMCA" on 14th Street for replacing a fat white man in a red suit with a fat white man in a snowman suit. What's the lefty Y's excuse? "We realized that change is sometimes good, and that Frosty is a great winter character who would appeal to a broader number of kids," according to the McBurney Y's executive director, John Rappaport. What a... non-controversy.

But the Post also spoke with the Catholic League's Bill Donohue, who's pretty pissed off: "Christmas is not about Jack Frost; it's not about snowmen. We're not talking about some secular organization that has no religious roots. If they can't celebrate Christmas, then they should check out. What a bunch of cowards." Yes, grown men are angry that Santa Claus has been replaced at a community center by an equally fictional character.

Spoiler alert, Bill: SANTA ISN'T REAL.

[Full disclosure: I'm a member of the McBurney Y — it's a great place! There's an indoor track, a nice pool, and the locker room after 2pm turns into an over-80 Jewish men's bar that's better than Max Fish.]